int a=13;
int b=5;

void setup() {
  // put your setup code here, to run once:
pinMode (a,OUTPUT);
pinMode(b,INPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
boolean b=digitalRead (b);
if (b==1)
{
  digitalWrite(a,LOW);
}
else
{
  digitalWrite(a,HIGH);
}
}
